急性胎盘缺血时脐血流改变的实验研究

目的 研究在不同胎盘缺血情况下胎羊脐带动静脉血流信号的变化。方法 双胎妊娠母羊2只，分别对其胎羊进行结扎脐动脉，结扎胎盘小叶及螺旋脐带等处理，观察脐血流的改变。结果 结扎—根脐动脉使脐血流阻力增高，胎盘小叶被结扎60％时，脐动静脉血流均有改变。结论 胎盘代偿功能正常下出现胎盘缺血情况，胎羊通过一系列生理调节将脐血流维持在正常范围，胎盘功能失代偿时，先出现脐动脉血流变化，继而出现不可逆脐静脉血流变化。在胎盘缺血情况下，脐带螺旋易引起脐血流改变。

Cord Blood Flow Change in Fetal Sheep During Acute Maternal Placenta Ischemia

Objective To study the cord artery and vein blood flow change during different placenta ischemic states.Methods Two twin pregnant sheep were tested by ligating cord artery or placenta cytelydon, and then spiraling several rounds, blood flow change were observed. Results When one cord artery was ligated, the resistance of cord artery blood flow increased, when 60% cytelydon were ligated, both cord artery and vein blood flow changed. Conclusion Under normal placenta condition, when ischemia happened, fetal sheep would keep the blood flow in place by physical adaptation. When the compensation ability of placenta lost, irreversible change of vein blood flow began, and even the least spiral of cord would cut the cord blood flow down.